Clock.



J. J. BUSENBENZ.

CLOCK.

, mmcmon HLED OCT. II. 1915. RENEWED mun-1,1911. 1,256,872.

M n; m j, 2 m a 1,1. BUSENBENZ.

CLOCK.

APPLICATION FILED OCT. H, l9l5- RENEWED JUNE 14, I917.

1,256,872. I Patented Feb. 19, 1918.

2 SHEETS-SHEET 2.

xwx V J31 4% fly/J UNITED STATES PATENT OFFICE.

JACOB J. BUSENBENZ, OF GRAND RAPIDS, MICHIGAN, ASSIGNOR 'IO DIFFERENTIAL CLOCK COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

CLOCK.

' Application filed October 11, 1915, Serial No. 55,198.

To all whom it may concern:

Be it known that I, JAcon J. BUsENBENz, a citizen of the United States, residing at Grand Rapids, in the county of Kent and State of l\Iichigan, have invented a new and useful Improvement in Clocks, of which the following is a specification.

My present invention relates to improvements in the power-transmission mechanism set forth in Letters Patent of the United States No. 973,854, granted to me October 25, 1910, in which a helical spring connects a relatively powerful primary motor and a clock-movement to drive the latter without expending much if any more power than suffices for the purpose. To this end, the helical power'transmission spring cooperates with an enlargement in a core for regulating the extent of tensioning the trainactuating section of the spring.

For the purposes of explanation, the accompanying drawings show and the following description sets forth my improvements as incorporated in a long-period clock, and particularly in a clock-movement of the lever type, for which I have more especially devised them, although I also contemplate their use and wish to be understood as intending to herein cover them in commercial time-devices, such as time-stamps, automaticmeteorological instruments, time-recorders and time-dating devices, graphic volt and watt meters, thermostats, recording pyrometers, and other instruments and devices for which they may be suitable.

The salient features of improvement relate to the helical power-transmission spring, which I provide as an open-coil spring, meaning that the turns are maintained out of frictional contact with each other, say to the extent of about .003 to .005 of an inch; to the extremities of the bearings (pinion and gear hubs) for the end-sections of the helical spring, which are beveled, with the advantage hereinafter explained; and to materially shortening the driving portion of the helical spring, by eliminating almost entirely its advance-end portion from the driving function and causing that function to be exerted only by the intermediate coils of the spring which immediately cooperate, for its tensioning purpose, with the enlargement in the core.

In the accompanying drawings. Figure 1 is a view in sectional rear elevation showing Patented Feb. 19, 1918.

Renewed June 14, 1917. Serial No. 174,779.

a lever type of clock-movement provided with my improvements, the section being taken on line 1, F 1g. 2; F 1g. 2 shows the same by a view in side elevation; Flg. 3 is an enlarged section on line 3, Fig. 1, and Fig.

4 is a section on line 4, Fig. 3.

The clock may, generally speaking, be of known construction, so that more reference to parts for identifying them will suflice. The central arbor 5, journaled in the frame 6 and carrying the hourhand 7, and the sleeve 8 on the arbor, carrying the minute-hand 9 are suitably connected through the medium of a geartrain with a relatively powerful spring motor, the casing of which is shown at 10. The end-gear 11 of this train meshes with a pinion 12, of the lantern-type, rotatably surrounding a bearing-sleeve 13 (Fig. 3) immovably fastened about the core-feature 14 of my improved regulating device. This core, as shown, is of the general construction of and for the same purpose as that in United States Letters Patent No. 1,069,316, granted to me August 5, 1913, and involves an intermediate wedge-section l5, beyond which the core is threaded to work in the hollow stem-portion 16 of a sectional head 16 forming a resiliently expansible enlargement of the core, and in which the wedge is adjustable to effect expansion and contraction of the enlargement for the regulating purpose explained in the last-named patent. The core is supported at its inner or rear end in a hollow head 17 on a stem 17 extending at its end into a suitable bearing 18 and carrying, to rotate about it, a gear-wheel 19 having a sleeve-extension 19 for which the stem 17 forms a bearing. This gear-wheel has an elongated sleeve-like hub 19 reaching short of one side of the enlargement 16 and surrounding the latters stationary stem-portion 16 and the pinion 12 has a relatively short hub 12*.

The gear 19 meshes with a pinion 20 on a shaft 21 carrying a gear 22 which meshes with a pinion 23, on a shaft 23 to operate the escapement, denoted, as a Whole by the reference-numeral 24.

The helical spring 25 tightly hugs at one of its end-sections the hub 12, so as to be twisted by the latter in turning under the recoil force of the primary motor, the op- .osite end-section of this spring similarly ugging the hub 19 for rotating the gear 19 by the force of that end-section in unwinding. The intermediate coils of the helical power-transmission spring, shown as four in number, surround the enlargement 16, with which they are represented in Fig. 3 as being out of contact. The hubs are shown to be slightly beveled, at 26 and 2. respectively, on their opposite inner ends.

The unwinding of the primary-motor spring turns the pinion 12 to wind the coils of the spring 25 which surround the enlargement 16 into contact with the latter, which momentarily arrests further unwinding of the motor-sprin and stores sufficient power in the aforesaid. four coils for rotating the wheel 19 to run the clock. As this stored power becomes expended, further unwinding of the motor-spring repeats its described action. Thus the clock-movement is always subjected to a uniform actuating force,'irrespective of the veakening of the power of the motor-spring in unwinding, which is a material advantage to all clocks employing my helical power-transmitting spring, whether the clocks be of the long-period or other variety.

The coils of the spring 25 being open or separated, while the spring is under the torsional strain of the 1110;01', the slightest contact of any one with another is avoided. Such contact would immediately affect the transmission of power prolonging the periods of transmission. \Vith these springcoils in contact with each other, as represented in the aforesaid Patent No. 973,83l, the impulses of the primary-motor spring are from 8 to 30 minutes apart, which is not so objectionable for a pendulum movement, but very objectionable for a lever-movement, since it produces excessive variation in the time-keeping. With the spring-coils separated, as herein shown and described, these impulses number about 200 per minute, which enables placing the spring 25 between the escapement and central arbor, to cause the primary-motor spring to directly drive that arbor under the control of the powertransmitting sprin which actuates the movement-operating escapemen instead, as formerly, of placing it between the central arbor and primary motor to cause the unwinding of the spring of the latter to drive the central arbor through the clock-movement, which increases the variation in torque on the transmitted side; and since variation in torque is decreased directly as the frequency of transmission is increased, increasing the frequency of transmission of power from the primary-motor spring is of the utmost importance in the functional operation of the spring 25, or governor.

The tapering of the hubs at 26 and 27, as represented in Fig. 3, is greatly exaggerated. In practice the taper extends backwardly from the respective hub-end a distance substantially equal to the diameter of the wire of the spiral spring, thus about .031 of an inch; and the inclination toward that end should be about 2 to 3 degrces.

The effect of the tapering is to prevent longitudinal crowding by the spring against, and resultant end-friction of, the pinion 12 or gear 19, or either of them. As will be understood, the torsional strain in the coils of the spring 25 about the enlargement 16 between the two'hubs 12' and 19, in contracting them, naturally contracts to a lesser diameter than that of the hubs the coils which cross the edges of the latter. Therefore, if the diameter of each hub were uniform throughout its length, its inner end would form a vertical shoulder, so that a spring coil passing from the hub at such shoulder, and assisted by the round crosssection of the wire and by the contracted condition set up in the coils in the space between the hubs, would cause the objectionable crowding referred to. By tapering the hubs at their opposite inner ends, the respective coils land gradually on the stationary enlargement 16, thereby avoiding production of the aforesaid end-friction and causing transn'iission of the primary-motor power through the spiral spring without loss, and to that extent promoting the desired frequency of transmission of that power.

By providing for transmitting the move ment-actuating power only from the intermediate coils of the helical spring, instead of from the end thereof, as formerly, the transmission-coils form a bridge between the two hubs, which tends to establish and maintain a point of equilibrium. In the moment of this equilibrium being established in the coil to the left-hand end of the series thereof about the enlargement 16 (Fig. 3), the two successive coils are tensioned in the same moment about the enlargement by the surplus power in the spring of the primary motor, while the power at the escape 24: reacts to the first-named coil, where the two forces are at zero, or theo retically at equilibrium. Inasmuch, however, as the power is expended at the escape, this equilibrium is instantaneously affected, and will be immediately restored from the reserve force of the primary-motor spring; and this operation is repeated until the excess energy of the motor is exhausted. It will therefore be apparent that the oftener this restoration can be perfoaned within a given time, the less will be the variation in the torque at the escape; and since maintenance of an even torque at the escape is essential for good time-keeping of the clock, the importance of this frequency in power-transmission will be realized, particularly when the fact is stated that high-grade household lever clocks embodying the hereindescribed improvements run with great accuracy and for any desired length of period, up to, say 400 days.

By way of further explaining the advantages of the present improvements in clockmovements, particularly when used for operating special commercial instruments requiring much power coupled with accuracy in time, the following may be stated.

Locating the governor-mechanism, in volving the helical spring 25, placed between the central arbor, or hour-shaft, and the escapevlieel, as shown and described, divides the movement into two units, namely, a primary-power unit and a differential or, timing unit, which last-named unit represents the torsional power imparted by the power-unit to the helical spring. Thus, as will be seen, the central arbor is directly actuated by the power-unit; and since all commercial devices are operated from the central arbor, or hour-shaft, and, besides, since the power-unit can be constructed to operate with any desired amount of power without in the least disturbing the fixed or predetermined torque required for operating the timing unit, a condition essential for imparting good time-keeping qualities to the movement is provided.

The present improvements, furthermore, enable a small andinexpensive movement of the lever-type to be made to operate colossal hands on dials of very large diameter, such as the dials of window, street and tower clocks, since the hands are directly operated from the power-unit of the movement, and the advance of the minute-hand from space to space is far less noticeable than in towerclocks as heretofore constructed.

From the foregoing explanatory description it will be seen that the advantages of my present improvements, particularly when applied to lever-movements, are due to the maintenance of uniform torque at the escapewheel; to the maintenance of sufficient re-' serve-power in the power-unit to instantly replace the power expended through the escape-wheel; and to controlling the excesspower, which must, at all times exceed the actual torque set up in the free or intermediate section of the governor, or helical spring 25, and properly termed the active torque required for operating the timemeasuring unit.

These factors go to establish the normal working condition under which my improved power-transmitting mechanism, or differential governor, performs the function of holding back all excess power in the power-unit and maintaining uniform torque at the escape-wheel in the timing unit.

I realize that considerable variation is possible in the details of construction thus specifically shown and described, and I do not intend by illustratin a single, specific or preferred embodiment o my invention to be limited thereto; my intention being in the following claims to claim protection upon all the novelty there may be n my invention as fully as the state of the art will permit.

What I claim as new and desire to secure by Letters Patent is 1. In a clock movement, the combination with a primary motor, of a clock-train, a core, a pinion geared to said motor and having a hub extendin over one portion of the core, a hub securec to a gear wheel of the clock-train and extending over another portion of the core, an enlargement on the core between the hubs, a helical spring surrounding both said hubs and enlargement with the end portions of the spring tightly wound about the hubs and the entire portion of the spring between the hubs extending over the enlargement with its coils out of contact with each other whereby the torsioning of the spring will occur only over the enlargement and between the adjacent ends of the hubs.

2. In a clock movement, the combination with a primary motor, of a clock-train, a core, a pinion geared to said motor and having a hub extending over one portion of the core, a hub secured to a gear wheel of the clock-train and extending over another portion of the core, the inner ends of said hubs being tapered, an enlargement on the core between the hubs, a helical spring surrounding both said hubs and enlargement with the end portions of the spring tightly wound about the hubs and the entire portion of the spring between the hubs extending over the enlargement with its coils out of contact with each other whereby the torsioning of the spring will occur onl over the enlargement and between the a jacent ends of the hubs.

3. In a clock movement, the combination with a primary motor, of a clock-train, a core, a pinion geared to said motor and having a hub extending over one portion of the core, a hub secured to a gear wheel of the clocktrain and extending over another portion of the core, an enlargement on the core between the hubs, a helical spring surrounding both said hubs and enlargement with the end portions of the spring tightly wound about the hubs and the entire portion of the spring between the hubs extending over the enlargement with its coils out of contact with each other whereby the torsioning of the spring will occur only over the enlargement and between the adjacent ends of the hubs, and means for varying the diameter of the enlargement.

4. In a clock-movement including an escapement, the combination of a primary motor having the hour-shaft arbor geared to it to form the power-unit, a core, a helical spring on the core having one end-section geared to said arbor for tensioning the spring by the motor-power and its opposite end-section geared to the escape-Wheel to form the time-measuring unit, and regulating means cooperating with the spring between its ends to limit the extent of tensioning it.

In a clock-movement including an escapement, the combination of a primary motor having the hour-shaft arbor geared to it to form the power-unit, a core, a helical spring on the core having its coils out of frictional contact with each other and one end-section geared to said arbor for tensioning the spring by the motor-power and its opposite end-section geared to the escape- Wheel to form the time-measuring unit, and regulating means cooperating with the spring between its ends to limit the extent of tensioning it.

6. In a clock-movement including an escapement, the combination of a primary motor having the hour-shaft arbor geared to it to form the power-unit, a core provided with an enlargement between its ends, a pinion journaled on one end of the core and geared to said arbor, a gearavheel journaled on the opposite end of the core and geared to the escape-Wheel, and a helical spring having one end-section tightly Wound about the hub of said pinion, its intermediate section Winding about said enlargement to limit the extent of tensioning, and its opposite end-see tion tightly wound about the hub of said wheel to form the time-measuring unit.

7. In a clock-movement including an escapement, the combination of a primary mo tor having the hour-shaft arbor geared to it to form the power-unit, a core provided with an enlargement between its ends, a pinion journaled on one end of the core and geared to said arbor, a gear-Wheel journaled on the opposite end of the core and gearet. to the escapeavheel, said pinion and wheel having hubs tapered on their respectively opposite ends, and a helical spring having one endsection tightly Wound about the pinion-hub, its intermediate section winding about said enlargement to limit the extent of tensioning, and its opposite end-section tightly Wound about the hub of said wheel to form the time-measuring unit.

GEO. B. TINI-IOLT, BENJ. F. SMITH.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents.

Washington, D. C." 

